1. Field of the Invention
The present invention relates to image forming apparatuses, such as a copier, a facsimile, a printer, etc., that transfer an image visualized on a surface of a latent image bearer onto a transfer member.
2. Discussion of the Background Art
In a well known image forming apparatus, a toner image is formed on a surface of a drum state photoconductive member that serves as a latent image bearer and is transferred onto an endless belt that serves as a transfer member. Such a belt member is generally wound around plural rollers and is rotated as one of the plural rollers is driven and rotates. When a driving force relay gear secured to a rotational supporting shaft of the photoconductive member includes eccentricity, a velocity of the photoconductive member fluctuates in one cycle showing a sine curve per rotation thereof. As a result, a latent image is written on the photoconductive member either expanded or contracted from an original shape. A toner image is then similarly transferred onto the belt member. As a result, the image shape is distorted.
Then, a conventional image forming apparatus attempts to suppress such image distortion using a prescribed method as discussed in Japanese Patent Registration No. 3186610.
Specifically, a motor commonly drives both of a photoconductive member and a driving roll while finely adjusting a driving velocity of the motor. However, the velocity of not only the photoconductive member but also the belt member necessarily fluctuates. Specifically even though the velocity fluctuation of the photoconductive member is suppressed by a certain degree, the velocity fluctuation of the belt remains and causes new image distortion. Therefore, it has been believed difficult to drive both the photoconductive member and the belt member with one common motor by simply finely adjusting the driving velocity thereof.